Hepatitis in Pregnancy Background
Acute viral hepatitis is the most common cause of jaundice in pregnancy. The course of most viral infections is not affected by pregnancy.
Hepatitis A virus (HAV) infection is the second most common form of viral hepatitis in the United States. It is a small RNA virus that is transmitted by the fecal oral route.[1, 2, 3] There is 1 worldwide serotype. Infections occur early in life in areas where sanitation is poor and living conditions are crowded. Vertical transmission of HAV during the pregnancy or puerperium is rare.[6, 7, 8, 9, 10] Pregnancy should not impact a physician’s management of HAV infection or vice-versa.
Hepatitis B virus (HBV) is the most common form of chronic hepatitis around the world. Chronic carriers can continue to transmit the disease for many years before becoming symptomatic. Infection occurs very often in early childhood when it is asymptomatic and then leads to the chronic carrier state. Chronic HBV infection leads to increased risk for chronic hepatic insufficiency, cirrhosis, and hepatocellular carcinoma.
Hepatitis C virus (HCV) was first identified in 1989.[12, 13] It is a major cause of chronic hepatitis, cirrhosis, and hepatocellular carcinoma around the world. HCV infection has a slow onset with symptoms in about 25% of patients. Approximately 40% of patients infected with HCV recover completely and the remainder become chronic carriers. Twenty percent of the carriers develop cirrhosis and of those, up to 20% develop liver cancer.
The delta antigen was first identified in the nucleus of hepatocytes infected with HBV.Hepatitis D is caused by the hepatitis delta virus (HDV). It is a defective RNA virus that can only cause hepatitis in individuals who are infected with HBV. It is transmitted percutaneously or sexually through contact with infected blood or blood products.
HDV uses HBsAg as its envelope protein essential for viral transmission.[17, 18] Chronic HBV carriers are at risk for infection with HDV. Individuals who are not infected with HBV and have not been immunized against HBV are at risk of infection with HBV with simultaneous or subsequent infection with HDV. Inoculation with HDV in the absence of HBV will not cause hepatitis D.
HDV infections can occur as a co-infection with HBV or as a superinfection on chronic HBV infection.
Hepatitis E is caused by the hepatitis E virus (HEV). Although initially thought to be hepatitis A, most waterborne epidemics of hepatitis in developing countries are known to be due to hepatitis E. It is rare and sporadic in industrialized countries. It is usually passed by fecal-oral transmission through a contaminated water supply. The infection is typically mild and self-limited without chronicity or clinical sequelae.
In 1966, GBV was identified after isolating a viral agent that led to a 3-week period of jaundice. The exposure presumably occurred during surgery in a young male surgeon named G. Barker. This led to the acronym GBV.
Subsequent development of new methods for viral identification allowed qualitative analysis of the virus with recognition of 3 related viral genomes: GBV-A, B and C. GBV-C was the virus identified as hepatitis G virus (HGV) and the only one capable of replicating in humans. The virus was subsequently detected in other individuals with parenteral hepatitis and was felt to be a new and separate hepatotropic entity.